Re-apply r127953 with fixes: eliminate empty return block if it has no predecessors; update dominator tree if cfg is modified.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127981 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 35a9bf7..891ea62 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -1805,6 +1805,16 @@
return HasRet;
}
+bool ARMTargetLowering::mayBeEmittedAsTailCall(CallInst *CI) const {
+ if (!EnableARMTailCalls)
+ return false;
+
+ if (!CI->isTailCall())
+ return false;
+
+ return !Subtarget->isThumb1Only();
+}
+
// ConstantPool, JumpTable, GlobalAddress, and ExternalSymbol are lowered as
// their target counterpart wrapped in the ARMISD::Wrapper node. Suppose N is
// one of the above mentioned nodes. It has to be wrapped because otherwise
diff --git a/lib/Target/ARM/ARMISelLowering.h b/lib/Target/ARM/ARMISelLowering.h
index 402e1c6..e09c1da 100644
--- a/lib/Target/ARM/ARMISelLowering.h
+++ b/lib/Target/ARM/ARMISelLowering.h
@@ -457,6 +457,8 @@
virtual bool isUsedByReturnOnly(SDNode *N) const;
+ virtual bool mayBeEmittedAsTailCall(CallInst *CI) const;
+
SDValue getARMCmp(SDValue LHS, SDValue RHS, ISD::CondCode CC,
SDValue &ARMcc, SelectionDAG &DAG, DebugLoc dl) const;
SDValue getVFPCmp(SDValue LHS, SDValue RHS,